Dynamic Typing in Python

In this tutorial, we will understand what’s dynamic typing in python.

Whenever we write a program in python, we come across a different set of statements, one of them is an assignment statement where we initialize a variable with a value.

Let us see how the assignment is different in the case of Python.

When we talk about languages like C, C++, and Java the memory is allocated based on the data type of variable and is accessed accordingly whereas python being a dynamically typed language it stores the value at some location and then combines the respective variable name with a container.

The data type is determined at the run time.

Consider the program given below-

Output:

<class 'float'>
<class 'int'>
<class 'str'>
36.0
72
datadatadata

Explanation:

Let’s have a look at the explanation of this program-

1. In the first step, we have initialized the variables a, b, and c with different types.
2. After this, we have checked their type that comes out to be float, integer, and string respectively.
3. In the next step, three of them are multiplied by three.
4. Since the data type is known at the run time, the operations are performed based on the type.
5. We can observe that the first value in the output is a float value, the next value is an integer, and a string is multiplied three times.
6. On executing the program, the expected output is displayed.

Relationship Between Objects, Variables and References.

The following sequence of steps happens when we assign a variable in Python-

1. We create an object in the memory that contains a value.
2. If the variable name doesn’t exist already, we can create it.
3. The reference is assigned to the object to the variable.

Consider the program given below-

Output:

<class 'float'>
<class 'int'>
<class 'str'>
<class 'complex'>

Explanation:

Let’s understand what happened in the above program.

1. We have initialized the variable ‘a‘ with values of different data types.
2. After this, we have checked the type of ‘a‘ in each case.
3. From this, we can infer that-
   1. In the first case, a is a reference to a float object.
   2. In the second case, a is a reference to an integer object.
   3. In the third case, a is a reference to a string object.
   4. In the fourth case, a is a reference to a complex object.

Shared References

Before starting with this, let’s have a look at the program-

Output:

12.0
12.0

Explanation:

It’s time to understand what exactly happened here-

1. We have initialized the value of a as 12.0 and b as a.
2. After this, we have printed the values of both a and b that comes out to be 12.0

This is nothing but the concept of shared references which says that “Two variables can have the same reference.”

One more example would make it clearer.

Output:

84.0
12.0

Explanation:

Let’s have a look at the explanation of this program-

1. We have initialized the value of a as 12.0, b as a, and then again assigned ‘a‘ with a * 7
2. After this, we have printed the values of both a and b that come out to be 84.0 for a but 12.0 in the case of b because it is still referencing the first value of a.

The Disadvantage of Dynamically Typed Languages

The feature that makes a language like Java more convenient is that it is statically typed and so the bugs and the errors are reported at compile-time instead of run-time.

Therefore, it’s a major concern for the python developers that the errors are shown during the run-time and therefore they have to develop strategies to rectify them.

Conclusion

Culminating the tutorial, we can say that python is a dynamically typed language and here we understood what are the distinct characteristics that can be observed while working on it.